After lots of hard work I finished my subwoofer. After turning it on I heard a clicking sound and then came the silence. No more output form my sub amp.

Fuse was still good, so I got my amp back out to check what happened. So here the embarrasing part, when soldering the positive speaker output I leaked some of the alloy to the housing of, I think it is, the opamp (metal square block).

Now I think I ruined the opamp but I can not find out wich type of part it is (type number or something).